Grinding machine



' Feb. 27, 1934. A, EALD 1,94%,915

GRINDING MACHINE Filedv June 5, 1931 2 Sheets-Sheet l Feb. 27, 1934., R. A. HEALD GRINDING MACHINE Filed June 5, 1931 2 Sheets-Sheet Patented Feb. 27, 1934 UNITED STATES PATENT OFFICE The Heald Machine Company,

Worcester,

Mass., a corporation of Massachusetts Application June 5, 1931. Serial No. 542,249

22 Claims. (01. 51--50) This invention relates to grinding machines and particularly to internal grinding machines which are used for grinding the internal cylindrical or conical surfaces of sleeves, gears, bushings and like articles.

In grinding with a machine of the type disclosed in Patent No. 1,682,672 issued August 28, 1928 to Guild or of the type disclosed inPatent No. 1,731,719 issued October 15, 1929 to Kempton and Gallimore, the grinding wheel enters the work and is .reciprocated therein to produce a rel ative traversing movement between the wheel and the work until the workpiece is ground to the desired finished size when the wheel is automatically removed from contact with the workpiece and is run out automatically to its rest position. In such machines, the wheel is fed transversely against the surface being ground, in order that the wheel will cut progressively deeper and deeper into the workpiece, by a relative cross-feed movement of said grinding wheel and work, which.

movement is imparted in a step-by-step relation by automatic mechanism responsive to the relative traversing movement, said cross-feed mechanism being actuated during the entire operation of the machine. The progressive cross-feed which urges the wheel against the surface being ground carries the wheel with greater and greater pressure against-the workpiece, the surface of the workpiece being removed to a less depth than the corresponding movement of the wheelhead toward the workpiece; This pressure causes the spindle carrying the wheel to be sprung somewhat and this spindle spring together with the excessive pressure built up between the wheel and work produces an uneven grinding action with the result that the finished surface is rough and often irregular. During the normal reciprocatory movement of the wheel over the surface being ground the pressure established by .the cross-feed movement is distributed over the entire width of the grinding wheel. However, when the wheel is being separated from the work at k the completion of the grinding, the pressure area is diminished, and the pressure for each unit of area is thereby increased as the wheel is being withdrawn beyond the end of the bore of the 9 workpiece, with the resultant bell-mouthing in the bore of said workpiece, producing a ground 0 surface which is not uniform throughout.

The patent to Kempton and Gallimore, above cited, provides for a reduced cross-feed movement during the final grinding'operation, which provides a more even finished surface, although the objectionable bell-mouthing still occurs when the wheel is separated from the work.

Ideal grinding conditions prevail when there is practically no pressure exerted by the wheel against the work, and the object of the present so invention is to provide a grinding machine which will relieve the pressure built up by the cross-feed movement of the grinding wheel, prior to withdrawal of the wheel from the work and which incorporates the advantages of a grinding machine 35; of the type disclosed inthe above cited patent. According to the present invention, the crossfeed movement of the grinding wheel is discontinued before the wheel is withdrawn from the work so that the wheel in completing the grinding m is allowed to traverse the surface being ground without a cross-feed movement being imparted thereto, the small amount of spindle spring which .was built up during the operation of the crossfeed movement causing the wheel to grind under gradually diminshed pressure until the spring in the spindle is no longer effective or, in other words, until the grinding wheel sparks out after construction of the cross-feed and hand wheel mechanism.

Fig. 4 is an isometric view showing the relative positions of the elements constituting the hand wheel releasing mechanism.

Fig. 5 is a wiring diagram.

Like reference characters refer to like parts throughout the different figures.

Referring first to Fig. 1, an internal grinding machine is shown having the reciprocatory table or carriage 1 ordinarily provided in internal grinding machines. In such a machine, either the grinding wheel or the work to be ground may be carried on the table 1, the reciprocation of the latter being utilized in either case to produce a relative traversing movement between the grinding wheel and the work. As here shown, the table 1 supports and carries a wheelhead 2, while the work which is to be operated upon is held in a workhead 3, the latter being carried by a bridge 4, which spans the slideways provided by no the machine frame for the back and forth movement of the table 1.

The grinding wheel 5 is carried on a spindle 6 which is suitably journaled in the wheelhead 2, and any suitable means, which need not herein be described, is provided to rotate said spindle 6 and wheel 5. The workpiece which is held with in a suitable chuck carried by the workhead 3, is also rotated, but desirably at a slower speed.

The reciprocation of the table 1 to cause the rotating grinding wheel 5 to make the required interior traverse of the rotating workpiece may be imparted in any well known manner, as for instance by the use of the fiuid pressure controlling and reversing mechanism described in United States Letters Patent No. 1,582,468 to Heald and Guild, granted April 27, 1926. Such mechanism is now well-known in grinding machines and requires no detailed description. It is sufiicient to note for present purposes, that the driving means employed for the reciprocation of the table 1, be it hydraulic drive, gear drive, or any other type, procures the reversal of said table at each end of the latters normal working stroke by the use of spaced adjustable dogs '7 and 8, carried by the table 1 and adapted alternately to engage and to move a reversing member 10; the latter, during the grinding operation, when the wheel 5 is moving back and forth within the workpiece 6, is situated between the two dogs '7 and 8 in a position to be struck alternately by said dogs, and by its consequent movement, first in one way and then the other, effects the reversals in the travel of the table 1.

The above described mechanism is all old and well known in the art and of itself forms no part of the present invention. The latter involves the attainment, in connection with such orsimilar grinding machine instrumentalities, of the novel and useful objects and results hereinbefore set forth, which are initiated by and under the con-' trol of the actuating mechanism for obtaining the cross-feed for the machine, as disclosed in the drawings. In the present machine, the cross-feed between work and grinding wheel is obtained by moving the wheelhead 2 transversely of the reciprocatory table 1, but obviously, the invention is not limited in this respect, since the cross-feed mechanism, as hereinafter described, might as readily be applied to the transverse movement of the workhead 3.

The wheelhead 2 of the machine is mounted on a cross-slide,not shown, which is adapted to have an in and out movement on the reciprocatory table 1; the movement of the slide is obtained by rotation of a threaded shaft 11 held against longitudinal movement in the table 1, the shaft engaging an internally threaded member secured to the cross-slide. The rotation of the threaded shaft 11 to procure the in and out movement of the cross-slide is effected in the following manner:--

As the table 1 is reciprocated, a cam 12 which is 'adjustably mounted on a horizontal extension 13 of the workhead 3, engages a roller 14, Fig. 2, mounted on an arm 15 which is journaled on a stud 16 on the table 1, thereby rocking said arm upwardly. A pawl 17 which is pivotally mounted on the outer end of the arm 15 engages at each rocking movement of the arm with one of the teeth on a ratchet wheel 18, imparting a step-bystep rotary movement thereto. The ratchet wheel 18, Fig. 3, is rigidly secured by screws 20 to the hub of a hand wheel 21, both wheels being rotatably mounted as a unit on a drive r ng 22.. In order normally to hold the wheels against rotation on the ring, said ring 22 is provided on its periphery with a plurality of teeth 23, and the spaces between the teeth are releasably engaged by a detent on the inner end of bolt 24 which is mounted for radial sliding movement in the hand wheel and is held in engagement with the teeth by a spring 25. The drive ring 22 is journaled on the hub 26 of a gear 2'7, the latter being keyed or otherwise secured to the end of the shaft 11, and carries a stud shaft 28 on which are journaled a pair of integrally connected spur gears 30 and 31, the gear 30 of which is in mesh with the gear 27 and the gear 31 of which is in mesh with stationary gear teeth 32 integrally formed on a sleeve 33 on the shaft 11 and which for the purposes of the present application may be considered as rigidly secured against rotation to the table 1. The drive ring 22 rotates with the ratchet 18 and hand wheel 21 through engagement of the bolt 24 with the teeth 23 and when such rotation occurs the gears 30 and 31, carried by said ring 22 around the stationary gear teeth 32, are rotated on their own axis, this latter rotation being transmitted to the gear 27, thus imparting a rotation to the shaft 11 and accordingly transmitting the step-by-step rotation of the ratchet wheel to the shaft and moving the cross-slide in a step-bystep cross-feed motion.

The grinding wheel is withdrawn from the workpiece for a dressing operation before the grinding is completed and is again withdrawn after the final cut to rest position to permit insertion of an ungrcund workpiece, the withdrawal movements being controlled by the crossfeed mechanism in the manner disclosed in the above cited patent to Guild. It is suflicient to note, for.the purposes of the present application, that an annular cam ring 34, which is disposed about the hub of the hand wheel and rotates therewith, carries a cam projection 35 which, in the clockwise rotation of the hand wheel and ratchet, engages successively with two adjustable screws- 36 and 3'7, engagement with screw 36 causing withdrawal of the wheel for the dressing operation, and engagement with the screw 37 causing withdrawal of the wheel to rest position after the final grinding operation. 'The screw 36 is carried by a pivotal member 38, Fig. 5, and the rocking of that member, under the influence of the cam projection 35, causes engagement of two electrical contacts 40 and 41, Fig. 5. Similar movement of the screw 37, which is carried by a pivotal member 42, causes the engagement of electrical contacts 43 and 44. Engagement of the first contacts 40 and 41 causes the wheel dressing instrumentalities of the machine to be brought into operation while engagement of the contacts 43 and 44 causes longitudinal separation of the grinding wheel 5 from the workpiece 6, the former being moved to its extreme right hand position.

When the terminals 40 and 41 make contact, an electrical circuit is formed which causes the table 1 to have an amplified stroke to the right, in order to withdraw the grinding wheel 5 from the -work, and simultaneously causes a wheel dressing member or diamond 45 to move into the amplified path of said grinding wheel, thereby to true the periphery of the latter as it passes the point of said diamond. As shown by the wiring diagram, Fig. 5, electrical current may be supplied by a direct current generator 46 driven continuously by any suitable 'means, not shown, from the same source of power that is used for the rotation of the grinding wheel or the work spindle. One terminal of this generator 46 is a grounded, as shown at 47, and the other is connected by a supply lead 48 to one bar or plate 50 of a two-way switch, the latter being designated as a whole by the numeral 51 and being disposed as shown in Fig. 1, on the front of the machine. Said switch 51 provides a second contact plate or bar 52 adapted to be connected electrically to bar 50 by a connector 53, which is mounted on an oscillatory member 54. The latter is pivoted at 55 and in its normal position, as shown in Fig. 5, disposes the connector 53 in contact with and across the plates 50 and 52; in the other position of movable member 54, the connector 53 engages only the plate 50, thereby breaking the connection between plates 50 and 52.

The normal position of movable switch member 54 is that shown in full lines in Fig. 5, and under these conditions, the supply lead 48 from the generator 46 is connected to a lead 56 taken off of the plate or bar 52 of the switch 51. Said lead 56 runs to the coil of an electromagnet 57 disposed in the front of the machine. A return lead 58 from the coil'of the electromagnet 57 is connected to the contact terminal 40. When the terminals 40 and 41 are brought together, as above described, by the action of cam 35, the circuit through electromagnet 57 is completed, since the terminal 41 is grounded, as shown at 60, Fig. 5. This energizesthe electromagnet 57, causing attraction of an armature member 61, and the consequent elevation of its attached lever arm 62, these parts being pivoted at 63 on the front of the machine. Such movement of the lever arm 62, responsive to the engagement of cam 35 with screw 36, is made use of automatically to interrupt the grinding operation on the workpiece 6 for the dressing and truing of the grinding wheel 5, in advance of the final and finishing cuts taken by said wheel to bring the workpiece to the desired size. This involves the withdrawal of the grinding wheel 5 from the workpiece, and the disposal in the temporarily amplified path of movement of said wheel of the dressing device or diamond 45; these two operations are effected through the medium of the lever arm 62 in the manner fully described in the Heald and Guild Patent No. 1,779,094, granted October 21, 1930, in which the dressing device 45 is moved into operative position through the medium of fluid under pressure; it is sufficient to note, for purposes of this application, that, as described in the said Heald and Guild Patent No. 1,779,094, the dresser point 45 is lowered into operative position by the downward swingingmovement of a carrying member 64. When the lever arm 62 is moved, a downward extension 65 thereof communicates said movement to a valve, thus making the pressure fluid active, through suitable connections, against a piston, not shown, which is operatively associated with the member 64, thereby to swing the dresser point 45 from the inoperative position that it normally occupies down into its operative position in the path of grinding wheel 5. The present invention is not limited to the above described use of pressure fluid for disposing the dresser 45 in operative position; obviously, any other type of dresser moving mechanism may be used.

As before stated, the other operation inaugurated by said engagement is the automatic amplification of the reciprocatory path of table 1, to carry the wheel 5 past the dresser 45. As shown in Fig. 1, the left hand table dog 8 which limits the right hand movement of table 1, is carried by a block 66, which instead of being secured. directly to the table 1 as is the case with the block 67 of dog 7, is mounted so as to be capable of sliding freely, longitudinally of said table. Under normal conditions, when the table is making its usual working reciprocations to traverse the grinding wheel 5 back and forth within the workpiece, the block 66 of dog 8 is held in definite spaced relation to a block 68, which latter, the same as the block 67 of right hand dog 7, is a stationary block adapted to maintain its predetermined setting or adjustment longitudinally of the table 1.

The device employed to hold the slidable block 66 in spaced relation to the fixed block 68 is here shown as a latch lever 70 pivoted on block 68 and havingits free end disposed by gravity in abutting relation to a shoulder on block 66, thereby holding the block 66 at a predetermined distance to the right of block 68. When the latch member 70 is lifted to free its end from the shoulder, the normal connection between the sliding block 66 and the fixed block 68 is broken, and when this occurs on the right hand movement of table 1, the dog 8 will bear without effect against the member 10. Thus the right hand movement of the table 1 on this particular stroke will be extended beyond the usual reciprocatory working path and the grinding wheel 5 will be carried out of the hole in the workpiece to a point just beyond that occupied by the dressing device, which latter, as already described, has been moved into operative position as the amplified right hand travel of table 1 begins. This amplified right hand travel of table 1 involves relative sliding movement between said table and the block 66, owing to the obstruction which the reversing member 10 imposes against the dog 8 to prevent the block 66 from moving with the table; finally the block 66 brings up against the block 68, whereupon the solid backing thus afforded for the block 66 enables the dog 8 to shift the member 10. This procures reversal of the table 1 and the left-hand movement of said table thus inaugurated is caused to restore the parts automatically to normal position in the manner disclosed in the above identified patent to Guild.

Said single amplified reciprocation of the table 1 for wheel dressing purposes is, in the present invention, inaugurated automatically upon a predetermined preliminary amount of grinding having been done on each workpiece, by the making of electrical contacts through the terminals 40 and 41 as already described, thus moving the lever 62 about its pivot 63. The upper portion of the lever 62, upon movement of this lever during normal working traverse of the grinding wheel 5, engages and lifts the latch lever 70, thus causing the above described amplified movement of the table 1, which carries the grinding wheel 5 to the right past the diamond 45 and then to the left, again passing said diamond before resuming the normal reciprocatory traverse of the workpiece 6. Thereupon, by any suitable means, such as that shown and described in the aforesaid Patent No. 1,779,094 of Heald and Guild, the diamond 45 is rocked upwardly into the inoperative position that it normally occupies.

On this amplified right hand dressing stroke of the table 1, an arm 71, Fig. l, pivoted at 72, and

hangingby gravity in the position shown in Fig. l, strikes an arm 73, Fig. 5. of movable switch member 54, thereby rocking said switch member away from bar 52 into the dotted line position of Fig. 5, 50

which prevents a repetition of the dressing stroke and releases the armature 61, thereby restoring the lever arms 62 and 65 to normal position.

After the wheel dressing operation above described, and with the resumption of grinding upon the workpiece 6, the inward feeding of the grinding wheel 5 involves further clockwise rotation of the ratchet wheel 16 which ultimately carries the cam 35 into engagement with the screw 37. The parts are so set and adjusted, as hereinafter described, that this engagement takes place just as the workpiece 6 reaches the exact desired size; the consequent movement of rocking member 42 brings together the contacts 43 and 44 and completes the electrical circuit through a second magnet '74 since a lead '75 runs from the lead 48 to the coil of the electromagnet '74, and the other end of said coil is connected by a lead '76 to the contact 43 and the contact 44 is grounded the same as the contact 41, at 60. Thus the electromagnet '74 is energized, causing attraction of an armature member '77 pivoted, as shown in Fig. 5, on the same spindle 63 which forms thepivot for the armature member 61. The armature member 77 provides a lever arm '78 for cooperation with the left hand table dog 8 in the following manner:-

Said table dog 8, as shown'in Fig. 1, is pivoted to its carrying block 66, and normally rests by gravity against a pin, thereby to maintain its free end in position to engage and move the reversing member 10 at the end of the right hand normal working stroke of the table 1. When the magnet 74, in response to the grinding of the workpiece to the exact desired size, is energized, the lever arm '78 is raised into the path of dog 8, and the latter, on the right hand movement of table 1, by reason of its pivotal mounting is free to ride on the upper surface of said lever arm; thus the striking end of said dog 8 is carried clear of the reversing member 10, and the table 1 continues its movement to the right, carrying the grinding wheel 5 out of the workpiece and well past the then inoperative dressing device 45, said table ultimately carrying the grinding wheel 5 into the position illustrated in Fig. '1, and there being brought to a full stop by any suitable means, such for example, as shown in the aforesaid patent to Heald and Guild Patent No. 1,582,468. Thus with the coming to size of a given workpiece 6, the mechanism automatically secures the complete cessation of the grinding operation, and the full longitudinal separation of the grinding wheel from the workpiece, permitting full access to said workpiece for its removal from the machine, and the insertion in said machine of a new unground workpiece while the grinding wheel 5 is entirely out of the way.

On the return to working position, from the full withdrawal position shown in Fig. 1, an arm '79, pivoted-at '72 and hanging by gravity in the position shown in Fig. 1, strikes an arm 80 of movable switch member 54, thereby rocking said switch member so that its connector 53 is returned to the position shown in Fig. 5, in readiness for the energization, at the proper time in the grinding of the next workpiece, of the electromagnet 5'7 which inaugurates, as above described, the wheel dressing operation. 'As shown in Fig. 5, arms '73 and.

80 of movable switch member 54 are offset from one another, as are also the corresponding striking arms '71 and '79, respectively, of the table.

During the withdrawal for the dressing operation, the arm '79 is not carried far enough to engage the arm 80 so that the member 54 is not reversed until the wheel is moved into position for grinding a new workpiece.

From the foregoing, it will be apparent that rotation of the hand wheel and the cam 35 attached thereto must occur throughout the grinding operation in order to actuate the table control means to permit thedesired movements of the wheel relative to the workpiece to take place. The present invention in cooperation with the above mechanism, is arranged to permit the crossfeed movement of the grinding wheel to be discontinued at any time during the grinding operation and still to permit the hand wheel to rotate. thereby to obtain the withdrawal movements for dressing and for moving the wheel to rest position when a workpiece has been completed, by providing for relative movement between the drive ring 22 and the ratchet wheel and hand wheel. In order to accomplish this, the bolt 24 is recessed at 81 adjacent the upper end thereof, the recess providing angular converging surfaces 82 and 83, Fig. 2, forming a depending point 84 which is spaced from the lower surface 85 of the recess. A bracket 86 is mounted on an extension 8'7 of the table 1 carrying the cross-feed mechanism and is provided with elongated arcuate slots 88 by which the bracket is secured to the extension, machine screws 90 extending through the slots .and engaging selectively in a series of threaded openings 91 in the extension, thereby to secure any desired adjustment of the bracket. The bracket carries centrally thereof bearing members 92 between which a member 93 is pivotally mounted, the latter providing an arcuate cam portion 94 which conforms to the curve of the hub of the hand wheel and lies within the path of the recess in the bolt 24. As the ratchet wheel and hand wheel are moved clockwise by the reciprocation of the table 1, the bolt approaches the'arcuate portion 94 and the angular surface 82 engages with said portion'. Upon continued clockwise movement of the ratchet wheel the surface 82 rides onto the end of the arcuate portion 94 and causes withdrawal movement of the bolt 24 against the action of the spring 25, thereby removing the lower 'end of the bolt from engagement with the teeth 23. Continued movement of the pawl 1'7 acts only to rotate the ratchet and the hand wheel about thedrive ring 22 since the hand wheel is now entirely disconnected from said ring. By adjustment of the bracket 86, it will be apparent that the bolt may be withdrawn from the drive ring at any time during the grinding operation thereby to discontinue the transverse feed of the grinding wheel.

The wear on the grinding wheel is compensated for by mechanism disclosed in the .patent to Taylor No. 1,682,673, issued August 28, 1928, which comprises, of itself, no part of the present invention. It is suflicient to say that, on the mover ment of the table 1 to rest position after a workpiece is completed, the mechanism indicated generally at 95 actuates a compensating ratchet member 96 a small amount clockwise. The compensating ratchet is secured by a key 9'7 to the sleeve 33 and in the normal operation of the machine is held against rotary movement by the compensating mechanism 95 and the clockwise movement of the ratchet 96 changes the angular relation of the gear teeth 32 on the sleeve to the cross-feed mechanism, thereby causing advancement of the grinding wheel to compensate for wear, as is fully explained in the above cited patent.

When the hand wheel is rotated counterclockwise to withdraw the wheel from the advanced position to a position in which it will enter an unground workpiece, the hand wheel and ratchet wheel secured thereto rotate about the drive ring until the bolt 24 is released from engagement with the arcuate cam 94, at which time the detent on the bolt engages with the same tooth from which it was drawn during the cross-feed movement, and the cam 35 is accordingly in the same relative position to the drive ring as in the preceding grinding operation; as a result,

the grinding wheel will be withdrawn from the work during the succeeding grinding operation, when the cross-slide has reached the same position at which withdrawal occurred during the preceding operation.

In precision work this results in premature withdrawal of the wheel, since the diameter of the grinding wheel has been reduced by the dressing operation and by the inevitable wear during the grinding operation. The mechanism shown compensates for this wear by providing a series of teeth 23 on the drive ring. Accordingly, when the compensating mechanism 95, adjacent the end of the withdrawal stroke rotates the ratchet wheel 96 to compensate for the wear on the wheel, the drive ring 22 is rotated therewith, being held in frictional contact with said ratchet wheel by a circular ring' 98 which is pressed against said ratchet wheel 96 by a spring 100 which is held against rotation relative to said drive ring 22 by machine screws 101, the frictional engagement being sufiicient to overcome the friction between the hub of the hand wheel and the drive ring 22. When the hand wheel is now rotated counterclockwise to withdraw the grinding wheel for another grinding operation, the detent on bolt 24 engages a tooth on the ring 22 spaced somewhat from the one from which it was withdrawn in the preceding grinding operation. This changes the relative position of the drive ring 22 and cam 35 carried by the hand wheel so that, during the succeeding grinding operation, the grinding wheel is not withdrawn from the workpiece until the crossslide is moved beyond the position at which withdrawal occurred in-the preceding operation, the increased movement compensating for wheel wear. T

I claim,

1. In a grinding machine, a grinding wheel having an operative position and an extended inoperative position axially spaced from a workpiece, mechanism for procuring a cross-feed movementlbetjween said wheel and workpiece in operativeiosition, means actuated by said mechanism to procure movement of said wheel axially of said workpiece to inoperative position, and means to procure cessation of said cross-feed movement prior to withdrawal of the wheel in response to said mechanism.

2. In a grinding machine, means to procure a cross-feed movement between a grinding wheel and a workpiece, rotating mechanism to actuate said means connected thereto, means to disconnect said means from the mechanism, whereby to procure cessation of the cross-feed movement without discontinuing the operation of the rotating mechanism, and means responsive to conmovement.

3. In a cross-feed mechanism for grinding machines, a rotatable actuating member, means operatively connected thereto to procure a crossfeed movement between a grinding wheel and workpiece, means responsive to rotation of said actuating member to disconnect said means from said member, whereby to permit continued rota-. tion of said member and to discontinue the crossfeed movement, and means responsive to continued rotation of said actuating member to procure axis separation of the grinding wheel and workpiece subsequent to the cessation of the cross-feed movement.

4. In a cross-feed mechanism for grinding machlnes, a rotatable actuating member, means to procurea cross-feed movement, means normally connecting said member to said cross-feed means to procure actuation of said cross-feed means directly from said actuating member. adjustable means responsive to rotation of said actuating member to disconnect said connecting means, thereby to permit continued rotation of said member, independently of said cross-feed means, and means responsive to further rotation of said actuating member to procure axial separation of the grinding wheel and workpiece subsequent to the cessation of the cross-feed movement.

5. In a cross-feed mechanism for grinding wheels, a threaded shaft, an actuating member therefor, a drive ring operatively connected to said shaft, and on which said member is rotatably mounted, means positively to connect said memher and ring against relative rotation comprising a slidable bolt, and adjustable cam means adapted upon rotation of said member, to withdraw said bolt, whereby to permit said actuating member to rotate on said drive ring.

6. In a grinding machine, a grinding wheel having an operative position in engagement with a workpiece and an extended inoperative position axially spaced from said workpiece, means to procure a cross-feed movement between the grinding wheel and workpiece, rotating mechanism to actuate said means connected thereto, means responsive to movement of said rotating mechanism to procure movement of said wheel axially of the workpiece to inoperative position, and means to procure cessation of said crossfeed movement prior to movement of the wheel to inoperative position.

'7. In a grinding machine, a grinding wheel having an operative position in engagement with a workpiece and an extended inoperative'position axially spaced from said workpiece, means to procure a cross-feed movement between the grinding wheel and workpiece, rotating mechanism to actuate said means connected thereto, 13. means responsive to movement of said rotating mechanism to procure movement of said wheel axially of the workpiece to inoperative position, means to procure cessation of said cross-feed movement prior to movement of the wheel to in- 5 operative position, said last means comprising a member normally connected to said cross-feed means and the mechanism, and means to disconnect said member from the cross-feed means.

8..In a grinding machine, a grinding wheel having an operative position in engagement with a workpiece and an extended inoperative position axially spaced from said workpiece, mechanism for procuring a cross feed movement between said wheel and workpiece in operative position, means for actuating said cross-feed mechanism, means responsive to movement of said actuating means to procure movement of the grinding wheel axially of the workpiece to inoperative position, and means to procure cessation of said' cross-feed movement prior to movement of the wheel to inoperative position.

9. In a grinding machine, a grinding wheel having an operative position in engagement with a workpiece and an extended inoperative position axially spaced from said workpiece, mechanism for procuring a cross-feed movement between said wheel and workpiece in operative position,

means for actuating said cross-feed means,

10 means responsive to movement of said actuating means to procure movement of the grinding Wheel axially of the workpiece to inoperative position, and means to procure cessation of said cross-feed movement prior to movement of the wheel to inoperative position, said last means comprising means for releasing said cross-feed means from said actuating means.

' 10. In a cross-feed mechanism for grinding wheels, a cross-feed shaft, an actuating member therefor, a drive ring operatively connected to said shaft, and on which said member is rotatably mounted, means positively to connect said member and ring against relative rotation, and means responsive to rotation of said member to disconnect said member and ring, thereby to permit said actuating member to rotate on said ring.

11. In a grinding machine, a grinding member and a 'workholding member, a table on which one of said members is mounted, said table having an operative position in which the grinding wheel is in engagement with a workpiece in the workholding member, and an extended position in which said members are axially spaced from each other, means to procure a cross-feed movement of one of said members, rotary mechanism connected to said cross-feed means to actuate said means, means to disconnect said cross-feed means from said mechanism to procure cessation of the cross-feed movement, and means responsive to continued rotation of the mechanism to procure movement of said table from the operative position to its inoperative position subsequent to the cessation of the cross-feed movement.

12. In a grinding machine, a grinding member and a workholding member, a table on which one of said members is mounted, said table having an operative position for supporting the grinding member in engagement with a workpiece in the workholding member and an extended inoperative position in which the grinding wheel is axially spaced from said workholder, mechanism for procuring a cross-feed movement of one of said members when said members are in operative position, means for actuating said cross-feed mechanism, means responc sive to movement of said actuating means to procure movement of the table to inoperative position, and means to procure cessation of said cross-feed movement prior to movement of the wheel to inoperative position.

13. In a grinding machine, a grinding member and a workholding member, a table on which one of said members is mounted, said table having a normal reciprocatory movement with the grinding member in engagement with a workpiece in said workholding member, and an extended movement to procure axial separation of said members, mechanism for procuring a crossfeed movement between the members, rotary mechanism connected to said cross-feed means for actuating said means, said mechanism being rotated in response to the reciprocatory move- 75 ment of the table, means responsive to movement of said rotary mechanism to procure the extended movement of the table to withdraw the Wheel from engagement with the workpiece, and means to procure cessation of said cross-feed movement prior to movement of the wheel to inoperative position, said last means comprising a member normally connecting said crossfeed means and said rotary mechanism, and means to disconnect said cross-feed means and said mechanism.

14. In a cross-feed mechanism for grinding wheels, a cross-feed shaft, an actuating member therefor, a drive ring operatively connected to said shaft, and on which said member is rotatably mounted, means positively to connect said member and ring against relative rotation, and cam means operable upon rotation of said member to render said connecting means inoperative to permit relative movement of said actuating member and ring.

15. In a cross-feed mechanism for grinding wheels, a cross-feed shaft, an actuating member therefor, a drive ring operatively connected to said shaft, and on which said member is rotatably mounted, means positively to connect said member and ring, and adjustable cam means responsive to rotation of said member to render said connecting means inoperative to permit rotation of said actuating member relative to said ring, said actuating member having means thereon operable subsequent to the disconnection of said'member and ring to procure cessation of the grinding operation.

16. In a grinding machine, a grinding wheel having a traversing movement relative to a workpiece, a crossfeed mechanism, including a pawl and ratchet, responsive to said traversing mo ement to procure a crossfeed movement between said wheel and a workpiece, means actuated by said mechanism to procure an axial withdrawal movement between said wheel and the workpiece, and means to procure separation between said pawl and ratchet to procure cessation of said crossfeed movement prior to the withdrawal movement, said means to procure withdrawal including an adjustable time controlled mechanism.

17. In a grinding machine, a grinding wheel having a traversing movement relative to a workpiece, mechanism responsive to said traversing movement to procure a crossfeed movement between said wheel and workpiece, mechanism to procure withdrawal of said wheel from the workpiece before completion of the grinding operation and to procure cessation of the crossfeed movement, means to return said wheel to the'work, and further mechanism to procure separation of said wheel and work when the workpiece is ground to size.

18. In a grinding machine, a grinding member and a work-supporting member, a table on which one of said members is mounted, means to procure a crossfeed movement between said grinding member and a workpiece in said work-supporting member, means to procure movement of the table for a separation between said members before completion of the grinding operation and to procure cessation of the crossfeed movement, means to return said members to operative relation, and further mechanism to procure separation between said grinding member'and the workpiece when the latter is ground to size.

19. In a grinding machine, a grinding wheel, a mechanism to procure a crossfeed movement between said wheel and a workpiece, mechanism to procure withdrawal of said wheel from the workpiece before completion of the grinding operation and to procure cessation of the crossfeed movement, means to return said wheel to the work and further mechanism to procure separation of said wheel and work when the latter is ground to size.

20. In a grinding machine, a grinding wheel having an operative position and an extended inoperative position axially spaced from a workpiece, mechanism for procuring a crossfeed movement between said wheel and workpiece in operative position, means actuated by said mechanism to procure movement of said wheel axially of said workpiece to inoperative position, and means responsive to the crossfeed movement to procure cessation of said crossfeed movement prior to withdrawal of the wheel in response to said mechanism.

21. In a grinding machine, a grinding member and a workholding member, a table on which one of said members is mounted, said table having an operative position in which the grinding member is in engagement with a workpiece in the workholding member, and an extended position in which said members are axially spaced from each other, means to procure a crossfeed movement of one of said members, rotary mechanism connected to said crossfeed means to actuate said means, means to procure cessation of the crossfeed movement without interfering with movement of said mechanism, and means responsive to continued rotation of the mechanism to procure movement of said table to its inoperative position subsequent to the cessation of the crossfeed movement.

22. In a grinding machine, a grinding member and a workholding member, a table on which one of said members is mounted, said table having an operative position for supporting the grinding member in engagement with a workpiece in the workholding member and an extended inoperative position in which the grindingwheel is axially spaced from said workholder, mechanism for procuring a crossfeed movement of one of said members when said members are inoperative position, means for actuating said crossfeed mechanism, means responsive to movement of said actuating means to procure movement of the table to inoperative position, and other means responsive to movement of said actuating means to procure cessation of said crossfeed movement prior to movement of the wheel to inoperative position.

RICHARD A. HEALD.

III 

